Profit about to go up (4,2)
I believe the answer is:
cash in
'profit' is the definition.
'about to go up' is the wordplay.
'about' becomes 'ca' (abbreviation for 'circa').
'to go up' becomes 'shin' (shin can mean to climb).
'ca'+'shin'='CASH IN'
(Other definitions for cash in that I've seen before include "what piggy bank has?" , "Realise" , "Get ready" , "Exchange for money; seize an advantage" , "Take advantage of" .)